The present invention is directed to a method and a device for delivering a substance intradermally to a patient. The invention is further directed to a microneedle delivery device having a separable cartridge containing a unit dose of a substance for delivering the substance intradermally to a patient.
Subcutaneous injection devices using a cannula that penetrates deep into the skin or muscle are effective for delivering a pharmaceutical or other substance to a patient. However, the pain normally induced by the cannula has prompted the development of less painful delivery methods. Recently, a number of intradermal devices have been designed in which microneedles are adapted to penetrate the skin to an intradermal depth at which a drug or pharmaceutical agent can be delivered to the patient and at which the microneedles do not cause pain or significant discomfort to the patient.
The skin is made up of several layers, with the upper composite layer being the epithelial layer. The outermost layer of the skin, the stratum corneum, has well known barrier properties to prevent molecules and various substances from entering the body and analytes from exiting the body. The stratum corneum, which is a complex structure of compacted keratinized cell remnants having a thickness of about 10-30 microns, forms a waterproof membrane to protect the body from invasion by various substances and the outward migration of various compounds.
The natural impermeability of the stratum corneum prevents the administration of most pharmaceutical agents and other substances through the skin. Numerous methods and devices have been proposed to enhance the permeability of the skin and to increase the diffusion of various drugs through the skin for utilization by the body. Typically, the delivery of drugs through the skin is enhanced by increasing either the permeability of the skin or the force or energy used to direct the drug through the skin.
Delivering various substances through the skin is also attained by forming micropores or cuts through the stratum corneum. By piercing the stratum corneum and delivering a drug to the skin in or below the stratum corneum, many drugs can be administered effectively. In a similar manner, some substances can be extracted from the body through cuts or pores formed in the stratum corneum. The devices for piercing the stratum corneum generally include a plurality of micron-sized needles or blades having a length selected to pierce the stratum corneum without passing completely through the epidermis. Examples of these devices are disclosed in U.S. Pat. No. 5,879,326 to Godshall et al.; U.S. Pat. No. 5,250,023 to Lee et al., and WO 97/48440.
In some of above-noted samples micron-sized needles or blades deliver substances to the body by allowing the substance to diffuse through the pores or channels in the device. Many of these prior art devices do not provide a controlled delivery of a substance to the patient.
The prior methods and devices for the intradermal administration of substances have had limited success. Accordingly, a continuing need exists in the industry for an improved device for the administration of various drugs and other substances to the body.
The present invention is directed to a device for the intradermal delivery of a fluid substance through the skin of a patient. In particular, the invention is directed to a device having a separable cartridge containing a fluid substance, such as a drug or vaccine, and for delivering the substance below the stratum corneum of the skin to a depth at which the substance can be absorbed and utilized by the body.
The delivery device of the invention includes a housing for engaging the surface of the skin and a dispensing cartridge received within the housing for dispensing and delivering the substance to the patient. The housing is provided with a coupling member, such as a wrist strap, for holding the housing in engagement with the skin of the patient.
The cartridge defines an internal reservoir containing the substance to be delivered to the patient and at least one skin penetrating member is provided for delivering the substance intradermally to the patient. A fluid channel extends between the reservoir and the skin penetrating member. In the preferred embodiment, a plurality of skin penetrating members are provided in an array to deliver the substance intradermally to the patient. In the illustrated embodiments the skin penetrating members are an array of hollow microneedles. The cartridge includes a diaphragm or seal in the fluid channel to contain the substance within the cartridge reservoir. The cartridge includes a piercing member for piercing the seal and allowing the fluid substance to flow from the reservoir through the fluid channel to the skin penetrating members for delivery to the patient. The housing includes a hinged cover member with a cam positioned to contact and actuate the piercing member when the cover member is closed. The cover member is provided with a spring member to apply pressure to the cartridge and to the fluid substance when the cover member is closed. The pressure applied to the fluid causes it to flow through the fluid channel and the needles to be delivered intradermally to the patient. An indicator window can be provided in the cover member to provide an indication of when the cartridge is empty and the dispensing is complete.
Accordingly, a primary object of the invention is to provide an intradermal delivery device having a separable and disposable cartridge containing a substance and at least one skin penetrating member for delivering the substance to the patient.
A further object of the invention is to provide a device for penetrating the skin and delivering a unit dose of a substance through the skin substantially without pain to the patient.
Another object of the invention is to provide a device having a plurality of microtubes, needles, microneedles, blades or lancets for piercing the stratum corneum of the skin to a depth sufficient for delivering a substance through the skin of a patient.
A further object of the invention is to provide a delivery device having at least one skin penetrating member and including a cartridge having a collapsible chamber for containing a fluid substance to be delivered to a patient via the skin penetrating member.
Another object of the invention is to provide a cartridge for use with an intradermal delivery device wherein the cartridge is collapsible to permit application of a dispensing pressure to the fluid substance in the cartridge for delivering the substance intradermally to the patient.
Another object of the invention is to provide a device for delivering a substance to a patient wherein the device has a dispensing member in the form of a spring cooperating with a cartridge and an internal supply channel connecting a reservoir in the cartridge to at least one skin penetrating member for delivering the substance to the patient.
A further object of the invention is to provide a delivery device having a cartridge with at least one flexible or elastic wall that can be deflected inwardly to dispense a substance from a reservoir through a skin penetrating member for delivery to the patient.
Another object of the invention is to provide an intradermal delivery device including a cartridge having an internal chamber with a fluid outlet, a diaphragm, and a piercing member for piercing the diaphragm for delivering a substance to a patient.
These and other objects of the invention are substantially attained by providing an intradermal delivery device comprising a housing having an internal cavity dimensioned to receive a cartridge. The cartridge includes at least one skin penetrating member, and a channel providing fluid communication between a reservoir in the cartridge and the skin penetrating member.
The objects and advantages of the invention are further attained by providing an intradermal delivery device comprising a housing and a cartridge removably received in the housing. The cartridge has an internal reservoir containing a fluid substance to be delivered to the patient. The device includes at least one skin penetrating member which has a length sufficient to penetrate the surface of the skin of a patient. The skin penetrating members can be placed in fluid communication with the cartridge for delivering the substance in the cartridge to the patient.
A yet further object of the invention is attained by providing an intradermal delivery device which comprises a housing having a coupling member for attaching the housing to the surface of the skin of a patient. A cartridge is removably received in the housing. The cartridge has an internal reservoir containing a fluid substance to be delivered to a patient. The cartridge has at least one flexible wall. A dispensing member deflects the flexible wall inwardly with respect to the cartridge for dispensing the substance from the cartridge. At least one skin penetrating member is in fluid communication with the cartridge for delivering the substance from the cartridge to the patient.
The objects, advantages, and other salient features of the invention will become apparent from the following detailed description, which, in conjunction with the accompanying drawings, discloses preferred embodiments of the invention.